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Date:      Tue, 12 Aug 1997 23:27:08 -0600
From:      John-David Childs <jdc@denver.net>
To:        Julian Elischer <julian@whistle.com>
Cc:        freebsd-questions@freebsd.org
Subject:   Re: Please explain why this is a security hole in /etc/daily
Message-ID:  <19970812232708.44622@denver.net>
In-Reply-To: <33F12CB1.446B9B3D@whistle.com>; from Julian Elischer on Tue, Aug 12, 1997 at 08:40:33PM -0700
References:  <199708112038.WAA19822@curry.mchp.siemens.de> <19970812211715.37172@denver.net> <33F12CB1.446B9B3D@whistle.com>

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On Tuesday August 1997, Julian Elischer <julian@whistle.com>
 had this to say about "Re: Please explain why this is a security hole 
 in /etc/daily":

> John-David Childs wrote:
> > 
> > happens next if the "action" is "rm -f {} \;"    :=)
> 
> the symlink gets deleted?

The file pointed to by the symlink (/etc/master.passwd) gets deleted.

>From a posting to BUGTRAQ (and linux-security) last year by Zygo Blaxell:

>Folks, do NOT use 'find' on a public directory with '-exec rm -f' as 
> root. Period.  Ever.  Delete it from your crontab *now* and finish
> reading the rest of this message later. 

> * PROBLEM DISCUSSION AND EXPLOITATION

> The immediate security problem is that 'rm' doesn't check that
> components of the directory name are not symlinks.  This means that you
> can delete any file on the system; indeed, with a little work you can
> delete *every* file on the system, provided that you can determine the
> file names (though you might be limited to deleting files more than ten

I'll dig up the full article/thread if I have time tomorrow (or you can
search the BUGTRAQ archives...).

-- 
John-David Childs (JC612)       Enterprise Internet Solutions
System Administrator            @denver.net/Internet-Coach/@ronan.net
  & Network Engineer            901 E 17th Ave, Denver 80218
As of this^H^H^H^H next week, passwords will be entered in Morse code.



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